In the prior art, there is known, for example from the patent publications FI101200 B, FI 101199 B, FI 112039B, FI 112328 B and FI 113244 B, various methods and arrangements for separating two solutions mixed in dispersion into two solution phases in a liquid-liquid extraction separation cell. A first solution and a second solution, which is heavier than the first solution, can be separated from the dispersion of said solutions. Generally the cell arrangement includes side walls and a bottom, inside which there is defined a separation space. The cell has a feed end, through which the dispersion is fed into the cell, and a drain end, through which the first and the second solutions are arranged to be drained as mutually separated. In between the feed and drain ends, the cell is provided with separator elements, forming successive separation steps therebetween, where the lighter first solution (generally an organic phase) is separated into an upper solution phase, and the second solution is separated below the upper solution phase into a lower solution phase (generally an aqueous solution). The cell drain end is provided with an overflow chute, which is positioned transversally with respect to the flowing direction, and receives the first solution separated into the upper phase as overflow from the cell, from which overflow chute the solution is drained. In the flowing direction, in succession to the overflow chute and adjacently with it, there is provided a collecting chute for receiving the second solution as underflow from the cell. Riser pipes extend from the collecting chute to the cell, through which riser pipes the second solution can rise to the collecting chute, from which the second solution phase is drained.